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Fluidization limit and slip structure in aqueous concentrated slurry containing hydrophobic hetero-particles in the presence of polymer-dispersant

聚合物分散剂存在下含有疏水杂颗粒的水性浓缩浆料的流化极限和滑移结构

基本信息

批准号：
11450334
负责人：
HASHIBA Minoru
金额：
$ 9.41万
依托单位：
Gifu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

项目摘要

The SiC powders were pre-heated to evaluate the effect of the amount of free carbon and oxygen content on the surface of the SiC particles on the fluidity of the SiC slurries and the sintered density. Heating of the SiC powders at over 300℃ enhances the fluidity of the SiC slurries. The fluidity of C slurries was effectively enhanced by the addition of ammonium 2-naphthalene sulfonate formaldehyde condensate ( DEMOL-AS ) solution, compared with the addition of styrene/maleic copolymer ( SM ) solution with tetramethyl ammonium hydroxide ( TMAOH ) at pH 10-1 1. The SiC slurries with C and B_4C as sintering aids were prepared by controlling a pH of 10-11 with TMAOH and adding the optimum amount ofDEMOL-AS or SM to C content and then slip casting was conducted. The sintered body containing the SiC powders pre-heated at any temperatures was achieved the higher density of about 98 % Th. D. The SiC body of higher sintered density was possible to fabricate by controlling the addition of carbon, taking into account oxygen content on the surface of the SiC particles and the amount of free carbon.Zirconium acetate effectively enhanced the dispersion and fluidity of SiC slurries in the weakly acidic pH range. The optimum pH valuetod concentration of Zr-A for the SiC slurries were pH 3.5 and 0.5-1 wt % of the SiC, respectively. In aqueous media, Zr-A became a positively charged species. The SiC particles also exhibited a positively charged state at pH 3.5. Thus, the role of Zr-A in the dispersion of slurries should be interpreted as that of a depletion-stabilization mechanism.

对碳化硅粉末进行预热，考察碳化硅颗粒表面游离碳含量和游离氧含量对碳化硅浆料流动性和烧结密度的影响。SiC粉体在300℃以上加热，提高了SiC浆料的流动性。与苯乙烯/马来烯共聚物（SM）溶液和四甲基氢氧化铵（TMAOH）溶液在pH值为10- 11时的加入相比，2-萘磺酸铵甲醛缩合物（dmo - as）溶液能有效提高C浆的流动性。用TMAOH控制pH值为10-11，在C的基础上加入适量的dmo - as或SM，制备了以C和B_4C为助烧剂的SiC浆料，并进行了滑移铸造。在任何温度下预热后的烧结体均可获得98%左右的高Th密度。D.考虑到SiC颗粒表面氧含量和游离碳量，通过控制碳的添加量，可以制备出烧结密度较高的SiC体。在弱酸性pH范围内，醋酸锆能有效提高碳化硅浆料的分散性和流动性。Zr-A对SiC浆料的最佳pH值分别为pH为3.5和0.5-1 wt %。在水介质中，Zr-A变成带正电的物质。在pH为3.5时，碳化硅颗粒也呈现出正电荷状态。因此，Zr-A在浆料分散中的作用应被解释为一种消耗-稳定机制。